In a straddle-type vehicle such as a snowmobile, a driver conventionally sits on a seat having a substantially flat top surface with an upwardly extending back support at a rear end of the seat. The snowmobile seat typically extends over the snowmobile's chassis, extending rearward from a forwardly mounted gas tank to a rearward end of the vehicle. Ordinarily, the snowmobile seat is designed to accommodate the driver approximately midway along the vehicle so that the driver's mass, when straddling the seat and holding the handlebars, preferably aligns (in the vertical plane) with the center of mass of the vehicle, which generally enhances driver stability and vehicle performance.
When seated on the straddle-type seat of a snowmobile, the driver will usually prefer to sit with his buttocks and lower back supported by the top surface of the seat and an upwardly extending back support, respectively. This position is most comfortable because it provides the most support and positional stability. This spot could be referred to as the “Sweet Spot” since some seats have a high-quality foam padding in this area to increase comfort. Due to cost constraints, usually only a portion of the snowmobile seat has a “sweet spot” made of high-quality, high-comfort foam.
Although these prior-art snowmobile seats have been utilized for many years, they are sub-optimal in terms of comfort and ergonomics for at least two main reasons.
First, drivers near the two extremes of the human scale are sub-optimally accommodated. In other words, a driver with short arms and legs will tend not to sit in the same spot on the seat as a driver with long arms and legs, therefore making it difficult (or expensive) to comfortably accommodate all sizes of drivers on the “sweet spot” of the seat.
Second, there are two types of driving positions available on current snowmobiles. Certain models offer a driving posture in which the driver's knees are forward of his ankles and the hips are above the knees, while other models offer a different driving posture where the driver's knees are rearward of his ankles and the hips are below the knees. Although each vehicle is specific to one of the two particular driving postures, one may attempt to switch between these two driving postures thus driver is not on the “sweet spot” in both postures. Alternatively, an enlarged sweet spot that comfortably accommodates the driver is also generally considered impracticable because of the high cost of manufacturing a seat with an enlarged sweet spot.
In either of these scenarios, the prior-art snowmobile seats are inadequate because the drivers of varying height and/or drivers who adopt different driving postures are not, at all times, comfortably seated on the sweet spot of the seat.
Some snowmobile seats include an adjustable backrest support where the backrest or a portion thereof can be inclined at various angles. However, the sweet spot of the seat, upon which the driver sits, remains fixed. Thus, the aforementioned problems are not mitigated by the snowmobile seats having the adjustable backrest supports.
Therefore, there remains a need for a seat for a snowmobile which comfortably and stably accommodates a driver of different heights and/or a driver who adopts different driving postures.